Connectors, in particular heavy duty connectors, typically have a two-part housing consisting substantially of a lower housing part and a cover. In most cases, a contact element having a plug face is arranged in the lower housing part, the plug face being covered or hidden by the cover when the contact element is not connected to a mating contact element, in that the cover rests on the lower housing part and the housing is closed thereby. It is known in this case that the cover is attached to the lower housing part by means of a retainer. The retainer is typically attached to the lower housing part by means of screws. In order to be able to produce such a screw connection, corresponding threads have to be provided in the housing, in particular in the lower housing part of the housing. This entails additional effort which complicates the production of such connectors. However, if the housing of the connector is formed of a metal (as is typically provided), such a design is not a problem, since the metal that is used provides sufficient strength and thus the metal housing can reliably support the thread. However, it is difficult to also use such a design in housings formed of a plastics material, since plastics material is softer than metal and thus sufficient strength to allow the thread to securely attach the retainer for the cover to the lower housing part in the long term, also at higher ambient temperatures, can only be provided with difficulty.